Recently, body soaps, in bar form, have been developed to provide dual purposes of a body soap and a shampoo for the hair. Such body soap/shampoo compositions can include hair conditioners for softness and manageability of the hair and include a natural soap base or a combination of a natural soap base, e.g., a metal salt of a fatty acid, such as a sodium or potassium salt, with a synthetic detergent soap base so that the composition can cleanse the body as well as the hair while leaving the hair soft and manageable.
One example of such a product is disclosed in the Tibbetts, et al. U.S. Pat. No. 4,919,838. While such products are adequate for cleansing both the body and the hair, even when such products contain hair conditioners, such bar soaps are significantly alkaline, thereby damaging the hair cuticle at times, and leave a film of soap on the hair shaft that significantly dulls the natural hair shine.
Other alkaline hair-treating compositions that can cause significant damage to hair and leave the hair in a dull, non-shiny condition include alkaline permanent wave compositions, such as those disclosed in this assignee's Kolc, et al. U.S. Pat. No. 4,913,900; as well as tinting, frosting, and bleaching compositions; environmental conditions, such as climate and pollution; antidandruff shampoo compositions, and other treatments that leave a solid residue on the hair shaft.
The reducing agent step of a permanent wave process and, in particular, alkaline thioglycolates, can cause significant damage to the hair cuticle since alkaline salts of thioglycolic acid, e.g., the ammonium salt of thioglycolic acid (pKa=10.4) have acceptable waving efficiency only if the pH of solution exceeds 9. If the pH of the reducing agent composition is in the range of about 10 to about 12, the hair cuticle can be uplifted at a number of sites on the hair cuticle and the hair can be significantly dulled and remain dull even after oxidation to complete the permanent waving process.
A Japanese patent application, HEI 2-68303 discloses a composition that is capable of eliminating odor resulting from treating hair with a cysteamine hair processing agent. This composition has a pH of about 2.0-2.7 and contains 0.1-0.5 milliequivalent of free acid per milliliter. If the pH of this composition is above 2.7, removal of odor is insufficient; and if the amount of acid per milliliter is above 0.5 milliequivalent, the hair is hardened and damaged.
A published European patent application 0 401 454 teaches the use of at least 5% ascorbic acid for prevention of oxidative damage to the hair by hydrogen peroxide.
In accordance with the present invention, it has been found that a solution of weak acid having a pH in the range of about 2.0 to about 5.5, particularly having a pH of about 2.0 to about 4.0, and having at least 0.75 milliequivalent of free acid per milliliter of solution, repairs hair that has been damaged by an alkaline treatment, such as the reducing agent lotion step of the permanent waving process, while restoring full shine to dulled hair that has been dulled as a result of an alkaline treatment of, or retention of solid residue on the hair.